Winching Volt drops

[MrKev]

Having been disappointed with the performance of my T-max EW11000 winch (unknown history), I decided to have a bit more in depth look at what was going on electrically, and found out that I'm loosing quite a lot of energy in the solenoids - 180mV approx across the tin-can solenoid I'm using as an isolator, and about 0.5V across the Albright copy. These figures are hauling the truck along the flat, with the handbrake on a small amount to give a little more resistance.

Now, clearly It'll never pull the few hundred amps it's meant to if there's already 0.7V lost in the solenoid etc at this sort of load, but this loss will only go up as the load on the winch goes up.

Does anyone have any figures for volt drops across their isolators and solenoids in any situations, and ideally in comparable situations?

Thanks,

Kev

[errol209]

Does anyone have any figures for volt drops across their isolators and solenoids in any situations, and ideally in comparable situations?

A quick "schmooze of da web" suggests a typical voltage drop across biggish (250A rated) contacts per 100A could be 30mV or so, so your Albright's contacts aren't right at all, and the isolator isn't clever.

[zim]

Just remember.... the lower the voltage the higher the current.

G

[LandyManLuke]

What else have you checked?

Have you measured the resistance across the contacts, with the winch & battery disconnected?

Which contacts of the albright did you measure across?

What condition are the brushes in?

What is the wiring like? age? circuit?

What is the voltage across the battery whilst you are winching?

[MrKev]

A quick "schmooze of da web" suggests a typical voltage drop across biggish (250A rated) contacts per 100A could be 30mV or so, so your Albright's contacts aren't right at all, and the isolator isn't clever.

Yeah, I didn't think much of the tin-can solenoid when I got it, which was the solenoid pack, so I replaced it with the Albright copy. Should have perhaps used the real thing . I then needed to fit an isolator, and preferred the remote controlled solenoid, rather than the standard removable key type, so resurrected one of the tin-cans.

What else have you checked?

Have you measured the resistance across the contacts, with the winch & battery disconnected?

Which contacts of the albright did you measure across?

What condition are the brushes in?

What is the wiring like? age? circuit?

What is the voltage across the battery whilst you are winching?

1. No.

2. All of them - all about the same.

3. No idea.

4. Fresh wiring, I installed it myself. The circuit is the standard arrangement, direct from battery to isolator solenoid with 35mm², then more 35mm² to the Albright-copy. 70mm² to and from the winch, and 35mm² from winch back to battery negative.

5. It maintained around 14V.

I can try and make some more measurements later.

Kev

[MrKev]

I've made some resistance measurements for the contacts, using a LCR bridge at 120Hz, which seemed to be capable of reasonable mΩ readings.

Isolator: 13mΩ

Albright contacts: from 30 to 38mΩ, depending on which set.

It does stack up with the voltage drop readings made previously, in that the winch must have been drawing around 13A pulling the truck horizontally.

So, I think I should be throwing away the albright copy, and trying the real thing, plus seeing about improving the isolator somewhat - at least using two in parallel, if not finding something better.

Kev

[Mark]

Kev,

I think I have a genuine albright here if you want to try it out.

I am assuming you are looking at electrical grmlins as well as the nasty mechnical sounding ones your winch was making....

Mark

[MrKev]

Hi Mark. Yes please, it would be good to try one. I can make some new measurements and help to prove/disprove the theory.

I stripped the winch gearbox down since your experience with it, removed all the caramel sludge that was in there and replaced it with fresh grease. The thing now pays out on freespool almost under the weight of the rope (well, not much effort at all, anyway) and is a definate mechanical improvement.

I think I may need to replace a bearing in the motor as there's still a little bit of a rattle, but I thought I should check the rest of the system out properly, as a winch can only be as good as it's power supply, after all.

Certainly the thing I've got in there would be hopeless, as some simple calulations show:

It's supposed to be a 5.5HP motor, that's 4kW assuming 100% efficient, or at least 330 Amps. This suggests an effective winding impedance of around 30-40mΩ. As there are two contact to go through on the control solenoid, plus the isolator, that's a total load in the region of about 120mΩ, i.e. 1.2kW or 30% of what the winch should be rated for - not to even start thinking about the head dissipation in the contacts themselves.

These calculations seem to stack up with the performance of the winch under the like for like comparision we carried out against a truck with an EP9 in the front.

Kev